WSE allows you to digitally sign a SOAP Messages by overriding the SecureMessage method.

To sign a SOAP message

1. The following code example overrides the SecureMessage method.

public override void SecureMessage(SoapEnvelope envelope, Security security)
{

//Obtain the security token with which you want to sign the SOAP message with.

KerberosToken kerbToken = new 

KerberosToken("host/" + hostname + "@" + domainName);

// Add the security token.                
security.Tokens.Add(kerbToken);

// Specify the security token to sign the message with.
MessageSignature sig = new MessageSignature(kerbToken);

// Add the digital signature to the SOAP message.
security.Elements.Add(sig);

  }